I checked my manual and it has no part number listed for it? I just think it's odd, that Remington produced the barrel and probably installed the sights too, but can't tell you what sights they put on your particular gun?
Whereas Tru Glo produces so many different versions, they probably do not know, unless you talk to the right person who deals with Remington? But I still think Remington has to know what model sights they purchased or contracted from Tru Glo for their guns?
Sure Remington might want you to go through Tru Glo, but I think it's Remington's part to tell you what sight part you are in need of, to let Tru Glo know?